[net-next-2.6.git] / drivers / s390 / kvm / kvm_virtio.c

/*
 * kvm_virtio.c - virtio for kvm on s390
 *
 * Copyright IBM Corp. 2008
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License (version 2 only)
 * as published by the Free Software Foundation.
 *
 *    Author(s): Christian Borntraeger <borntraeger@de.ibm.com>
 */

#include <linux/init.h>
#include <linux/bootmem.h>
#include <linux/err.h>
#include <linux/virtio.h>
#include <linux/virtio_config.h>
#include <linux/slab.h>
#include <linux/virtio_console.h>
#include <linux/interrupt.h>
#include <linux/virtio_ring.h>
#include <linux/pfn.h>
#include <asm/io.h>
#include <asm/kvm_para.h>
#include <asm/kvm_virtio.h>
#include <asm/setup.h>
#include <asm/s390_ext.h>

#define VIRTIO_SUBCODE_64 0x0D00

/*
 * The pointer to our (page) of device descriptions.
 */
static void *kvm_devices;
struct work_struct hotplug_work;

struct kvm_device {
	struct virtio_device vdev;
	struct kvm_device_desc *desc;
};

#define to_kvmdev(vd) container_of(vd, struct kvm_device, vdev)

/*
 * memory layout:
 * - kvm_device_descriptor
 *        struct kvm_device_desc
 * - configuration
 *        struct kvm_vqconfig
 * - feature bits
 * - config space
 */
static struct kvm_vqconfig *kvm_vq_config(const struct kvm_device_desc *desc)
{
	return (struct kvm_vqconfig *)(desc + 1);
}

static u8 *kvm_vq_features(const struct kvm_device_desc *desc)
{
	return (u8 *)(kvm_vq_config(desc) + desc->num_vq);
}

static u8 *kvm_vq_configspace(const struct kvm_device_desc *desc)
{
	return kvm_vq_features(desc) + desc->feature_len * 2;
}

/*
 * The total size of the config page used by this device (incl. desc)
 */
static unsigned desc_size(const struct kvm_device_desc *desc)
{
	return sizeof(*desc)
		+ desc->num_vq * sizeof(struct kvm_vqconfig)
		+ desc->feature_len * 2
		+ desc->config_len;
}

/* This gets the device's feature bits. */
static u32 kvm_get_features(struct virtio_device *vdev)
{
	unsigned int i;
	u32 features = 0;
	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
	u8 *in_features = kvm_vq_features(desc);

	for (i = 0; i < min(desc->feature_len * 8, 32); i++)
		if (in_features[i / 8] & (1 << (i % 8)))
			features |= (1 << i);
	return features;
}

static void kvm_finalize_features(struct virtio_device *vdev)
{
	unsigned int i, bits;
	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
	/* Second half of bitmap is features we accept. */
	u8 *out_features = kvm_vq_features(desc) + desc->feature_len;

	/* Give virtio_ring a chance to accept features. */
	vring_transport_features(vdev);

	memset(out_features, 0, desc->feature_len);
	bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
	for (i = 0; i < bits; i++) {
		if (test_bit(i, vdev->features))
			out_features[i / 8] |= (1 << (i % 8));
	}
}

/*
 * Reading and writing elements in config space
 */
static void kvm_get(struct virtio_device *vdev, unsigned int offset,
		   void *buf, unsigned len)
{
	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;

	BUG_ON(offset + len > desc->config_len);
	memcpy(buf, kvm_vq_configspace(desc) + offset, len);
}

static void kvm_set(struct virtio_device *vdev, unsigned int offset,
		   const void *buf, unsigned len)
{
	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;

	BUG_ON(offset + len > desc->config_len);
	memcpy(kvm_vq_configspace(desc) + offset, buf, len);
}

/*
 * The operations to get and set the status word just access
 * the status field of the device descriptor. set_status will also
 * make a hypercall to the host, to tell about status changes
 */
static u8 kvm_get_status(struct virtio_device *vdev)
{
	return to_kvmdev(vdev)->desc->status;
}

static void kvm_set_status(struct virtio_device *vdev, u8 status)
{
	BUG_ON(!status);
	to_kvmdev(vdev)->desc->status = status;
	kvm_hypercall1(KVM_S390_VIRTIO_SET_STATUS,
		       (unsigned long) to_kvmdev(vdev)->desc);
}

/*
 * To reset the device, we use the KVM_VIRTIO_RESET hypercall, using the
 * descriptor address. The Host will zero the status and all the
 * features.
 */
static void kvm_reset(struct virtio_device *vdev)
{
	kvm_hypercall1(KVM_S390_VIRTIO_RESET,
		       (unsigned long) to_kvmdev(vdev)->desc);
}

/*
 * When the virtio_ring code wants to notify the Host, it calls us here and we
 * make a hypercall.  We hand the address  of the virtqueue so the Host
 * knows which virtqueue we're talking about.
 */
static void kvm_notify(struct virtqueue *vq)
{
	struct kvm_vqconfig *config = vq->priv;

	kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, config->address);
}

/*
 * This routine finds the first virtqueue described in the configuration of
 * this device and sets it up.
 */
static struct virtqueue *kvm_find_vq(struct virtio_device *vdev,
				     unsigned index,
				     void (*callback)(struct virtqueue *vq),
				     const char *name)
{
	struct kvm_device *kdev = to_kvmdev(vdev);
	struct kvm_vqconfig *config;
	struct virtqueue *vq;
	int err;

	if (index >= kdev->desc->num_vq)
		return ERR_PTR(-ENOENT);

	config = kvm_vq_config(kdev->desc)+index;

	err = vmem_add_mapping(config->address,
			       vring_size(config->num,
					  KVM_S390_VIRTIO_RING_ALIGN));
	if (err)
		goto out;

	vq = vring_new_virtqueue(config->num, KVM_S390_VIRTIO_RING_ALIGN,
				 vdev, (void *) config->address,
				 kvm_notify, callback, name);
	if (!vq) {
		err = -ENOMEM;
		goto unmap;
	}

	/*
	 * register a callback token
	 * The host will sent this via the external interrupt parameter
	 */
	config->token = (u64) vq;

	vq->priv = config;
	return vq;
unmap:
	vmem_remove_mapping(config->address,
			    vring_size(config->num,
				       KVM_S390_VIRTIO_RING_ALIGN));
out:
	return ERR_PTR(err);
}

static void kvm_del_vq(struct virtqueue *vq)
{
	struct kvm_vqconfig *config = vq->priv;

	vring_del_virtqueue(vq);
	vmem_remove_mapping(config->address,
			    vring_size(config->num,
				       KVM_S390_VIRTIO_RING_ALIGN));
}

static void kvm_del_vqs(struct virtio_device *vdev)
{
	struct virtqueue *vq, *n;

	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
		kvm_del_vq(vq);
}

static int kvm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
			struct virtqueue *vqs[],
			vq_callback_t *callbacks[],
			const char *names[])
{
	struct kvm_device *kdev = to_kvmdev(vdev);
	int i;

	/* We must have this many virtqueues. */
	if (nvqs > kdev->desc->num_vq)
		return -ENOENT;

	for (i = 0; i < nvqs; ++i) {
		vqs[i] = kvm_find_vq(vdev, i, callbacks[i], names[i]);
		if (IS_ERR(vqs[i]))
			goto error;
	}
	return 0;

error:
	kvm_del_vqs(vdev);
	return PTR_ERR(vqs[i]);
}

/*
 * The config ops structure as defined by virtio config
 */
static struct virtio_config_ops kvm_vq_configspace_ops = {
	.get_features = kvm_get_features,
	.finalize_features = kvm_finalize_features,
	.get = kvm_get,
	.set = kvm_set,
	.get_status = kvm_get_status,
	.set_status = kvm_set_status,
	.reset = kvm_reset,
	.find_vqs = kvm_find_vqs,
	.del_vqs = kvm_del_vqs,
};

/*
 * The root device for the kvm virtio devices.
 * This makes them appear as /sys/devices/kvm_s390/0,1,2 not /sys/devices/0,1,2.
 */
static struct device *kvm_root;

/*
 * adds a new device and register it with virtio
 * appropriate drivers are loaded by the device model
 */
static void add_kvm_device(struct kvm_device_desc *d, unsigned int offset)
{
	struct kvm_device *kdev;

	kdev = kzalloc(sizeof(*kdev), GFP_KERNEL);
	if (!kdev) {
		printk(KERN_EMERG "Cannot allocate kvm dev %u type %u\n",
		       offset, d->type);
		return;
	}

	kdev->vdev.dev.parent = kvm_root;
	kdev->vdev.id.device = d->type;
	kdev->vdev.config = &kvm_vq_configspace_ops;
	kdev->desc = d;

	if (register_virtio_device(&kdev->vdev) != 0) {
		printk(KERN_ERR "Failed to register kvm device %u type %u\n",
		       offset, d->type);
		kfree(kdev);
	}
}

/*
 * scan_devices() simply iterates through the device page.
 * The type 0 is reserved to mean "end of devices".
 */
static void scan_devices(void)
{
	unsigned int i;
	struct kvm_device_desc *d;

	for (i = 0; i < PAGE_SIZE; i += desc_size(d)) {
		d = kvm_devices + i;

		if (d->type == 0)
			break;

		add_kvm_device(d, i);
	}
}

/*
 * match for a kvm device with a specific desc pointer
 */
static int match_desc(struct device *dev, void *data)
{
	if ((ulong)to_kvmdev(dev_to_virtio(dev))->desc == (ulong)data)
		return 1;

	return 0;
}

/*
 * hotplug_device tries to find changes in the device page.
 */
static void hotplug_devices(struct work_struct *dummy)
{
	unsigned int i;
	struct kvm_device_desc *d;
	struct device *dev;

	for (i = 0; i < PAGE_SIZE; i += desc_size(d)) {
		d = kvm_devices + i;

		/* end of list */
		if (d->type == 0)
			break;

		/* device already exists */
		dev = device_find_child(kvm_root, d, match_desc);
		if (dev) {
			/* XXX check for hotplug remove */
			put_device(dev);
			continue;
		}

		/* new device */
		printk(KERN_INFO "Adding new virtio device %p\n", d);
		add_kvm_device(d, i);
	}
}

/*
 * we emulate the request_irq behaviour on top of s390 extints
 */
static void kvm_extint_handler(unsigned int ext_int_code,
			       unsigned int param32, unsigned long param64)
{
	struct virtqueue *vq;
	u16 subcode;
	u32 param;

	subcode = ext_int_code >> 16;
	if ((subcode & 0xff00) != VIRTIO_SUBCODE_64)
		return;

	/* The LSB might be overloaded, we have to mask it */
	vq = (struct virtqueue *)(param64 & ~1UL);

	/* We use ext_params to decide what this interrupt means */
	param = param32 & VIRTIO_PARAM_MASK;

	switch (param) {
	case VIRTIO_PARAM_CONFIG_CHANGED:
	{
		struct virtio_driver *drv;
		drv = container_of(vq->vdev->dev.driver,
				   struct virtio_driver, driver);
		if (drv->config_changed)
			drv->config_changed(vq->vdev);

		break;
	}
	case VIRTIO_PARAM_DEV_ADD:
		schedule_work(&hotplug_work);
		break;
	case VIRTIO_PARAM_VRING_INTERRUPT:
	default:
		vring_interrupt(0, vq);
		break;
	}
}

/*
 * Init function for virtio
 * devices are in a single page above top of "normal" mem
 */
static int __init kvm_devices_init(void)
{
	int rc;

	if (!MACHINE_IS_KVM)
		return -ENODEV;

	kvm_root = root_device_register("kvm_s390");
	if (IS_ERR(kvm_root)) {
		rc = PTR_ERR(kvm_root);
		printk(KERN_ERR "Could not register kvm_s390 root device");
		return rc;
	}

	rc = vmem_add_mapping(real_memory_size, PAGE_SIZE);
	if (rc) {
		root_device_unregister(kvm_root);
		return rc;
	}

	kvm_devices = (void *) real_memory_size;

	INIT_WORK(&hotplug_work, hotplug_devices);

	ctl_set_bit(0, 9);
	register_external_interrupt(0x2603, kvm_extint_handler);

	scan_devices();
	return 0;
}

/* code for early console output with virtio_console */
static __init int early_put_chars(u32 vtermno, const char *buf, int count)
{
	char scratch[17];
	unsigned int len = count;

	if (len > sizeof(scratch) - 1)
		len = sizeof(scratch) - 1;
	scratch[len] = '\0';
	memcpy(scratch, buf, len);
	kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, __pa(scratch));
	return len;
}

static int __init s390_virtio_console_init(void)
{
	if (!MACHINE_IS_KVM)
		return -ENODEV;
	return virtio_cons_early_init(early_put_chars);
}
console_initcall(s390_virtio_console_init);


/*
 * We do this after core stuff, but before the drivers.
 */
postcore_initcall(kvm_devices_init);
Commit	Line	Data
e976a2b9 CB	1	/*
	2	* kvm_virtio.c - virtio for kvm on s390
	3	*
	4	* Copyright IBM Corp. 2008
	5	*
	6	* This program is free software; you can redistribute it and/or modify
	7	* it under the terms of the GNU General Public License (version 2 only)
	8	* as published by the Free Software Foundation.
	9	*
	10	* Author(s): Christian Borntraeger <borntraeger@de.ibm.com>
	11	*/
	12
	13	#include <linux/init.h>
	14	#include <linux/bootmem.h>
	15	#include <linux/err.h>
	16	#include <linux/virtio.h>
	17	#include <linux/virtio_config.h>
5a0e3ad6	18	#include <linux/slab.h>
faeba830	19	#include <linux/virtio_console.h>
e976a2b9 CB	20	#include <linux/interrupt.h>
e976a2b9 CB	21	#include <linux/virtio_ring.h>
17f34580	22	#include <linux/pfn.h>
e976a2b9 CB	23	#include <asm/io.h>
	24	#include <asm/kvm_para.h>
	25	#include <asm/kvm_virtio.h>
	26	#include <asm/setup.h>
	27	#include <asm/s390_ext.h>
	28
	29	#define VIRTIO_SUBCODE_64 0x0D00
	30
	31	/*
	32	* The pointer to our (page) of device descriptions.
	33	*/
	34	static void *kvm_devices;
cefa33e2	35	struct work_struct hotplug_work;
e976a2b9	36
e976a2b9 CB	37	struct kvm_device {
	38	struct virtio_device vdev;
	39	struct kvm_device_desc *desc;
	40	};
	41
	42	#define to_kvmdev(vd) container_of(vd, struct kvm_device, vdev)
	43
	44	/*
	45	* memory layout:
	46	* - kvm_device_descriptor
	47	* struct kvm_device_desc
	48	* - configuration
	49	* struct kvm_vqconfig
	50	* - feature bits
	51	* - config space
	52	*/
	53	static struct kvm_vqconfig kvm_vq_config(const struct kvm_device_desc desc)
	54	{
	55	return (struct kvm_vqconfig *)(desc + 1);
	56	}
	57
	58	static u8 kvm_vq_features(const struct kvm_device_desc desc)
	59	{
	60	return (u8 *)(kvm_vq_config(desc) + desc->num_vq);
	61	}
	62
	63	static u8 kvm_vq_configspace(const struct kvm_device_desc desc)
	64	{
	65	return kvm_vq_features(desc) + desc->feature_len * 2;
	66	}
	67
	68	/*
	69	* The total size of the config page used by this device (incl. desc)
	70	*/
	71	static unsigned desc_size(const struct kvm_device_desc *desc)
	72	{
	73	return sizeof(*desc)
	74	+ desc->num_vq * sizeof(struct kvm_vqconfig)
	75	+ desc->feature_len * 2
	76	+ desc->config_len;
	77	}
	78
5ca9fd54 HC	79	/* This gets the device's feature bits. */
5ca9fd54 HC	80	static u32 kvm_get_features(struct virtio_device *vdev)
e976a2b9	81	{
5ca9fd54 HC	82	unsigned int i;
5ca9fd54 HC	83	u32 features = 0;
e976a2b9	84	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
5ca9fd54	85	u8 *in_features = kvm_vq_features(desc);
e976a2b9	86
5ca9fd54 HC	87	for (i = 0; i < min(desc->feature_len * 8, 32); i++)
	88	if (in_features[i / 8] & (1 << (i % 8)))
	89	features \|= (1 << i);
	90	return features;
	91	}
e976a2b9	92
c624896e	93	static void kvm_finalize_features(struct virtio_device *vdev)
5ca9fd54	94	{
c624896e	95	unsigned int i, bits;
5ca9fd54 HC	96	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
	97	/* Second half of bitmap is features we accept. */
	98	u8 *out_features = kvm_vq_features(desc) + desc->feature_len;
e976a2b9	99
e34f8725 RR	100	/* Give virtio_ring a chance to accept features. */
	101	vring_transport_features(vdev);
	102
5ca9fd54	103	memset(out_features, 0, desc->feature_len);
c624896e RR	104	bits = min_t(unsigned, desc->feature_len, sizeof(vdev->features)) * 8;
	105	for (i = 0; i < bits; i++) {
	106	if (test_bit(i, vdev->features))
5ca9fd54 HC	107	out_features[i / 8] \|= (1 << (i % 8));
5ca9fd54 HC	108	}
e976a2b9 CB	109	}
	110
	111	/*
	112	* Reading and writing elements in config space
	113	*/
	114	static void kvm_get(struct virtio_device *vdev, unsigned int offset,
	115	void *buf, unsigned len)
	116	{
	117	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
	118
	119	BUG_ON(offset + len > desc->config_len);
	120	memcpy(buf, kvm_vq_configspace(desc) + offset, len);
	121	}
	122
	123	static void kvm_set(struct virtio_device *vdev, unsigned int offset,
	124	const void *buf, unsigned len)
	125	{
	126	struct kvm_device_desc *desc = to_kvmdev(vdev)->desc;
	127
	128	BUG_ON(offset + len > desc->config_len);
	129	memcpy(kvm_vq_configspace(desc) + offset, buf, len);
	130	}
	131
	132	/*
	133	* The operations to get and set the status word just access
	134	* the status field of the device descriptor. set_status will also
	135	* make a hypercall to the host, to tell about status changes
	136	*/
	137	static u8 kvm_get_status(struct virtio_device *vdev)
	138	{
	139	return to_kvmdev(vdev)->desc->status;
	140	}
	141
	142	static void kvm_set_status(struct virtio_device *vdev, u8 status)
	143	{
	144	BUG_ON(!status);
	145	to_kvmdev(vdev)->desc->status = status;
	146	kvm_hypercall1(KVM_S390_VIRTIO_SET_STATUS,
	147	(unsigned long) to_kvmdev(vdev)->desc);
	148	}
	149
	150	/*
	151	* To reset the device, we use the KVM_VIRTIO_RESET hypercall, using the
	152	* descriptor address. The Host will zero the status and all the
	153	* features.
	154	*/
	155	static void kvm_reset(struct virtio_device *vdev)
	156	{
	157	kvm_hypercall1(KVM_S390_VIRTIO_RESET,
	158	(unsigned long) to_kvmdev(vdev)->desc);
	159	}
	160
	161	/*
	162	* When the virtio_ring code wants to notify the Host, it calls us here and we
	163	* make a hypercall. We hand the address of the virtqueue so the Host
	164	* knows which virtqueue we're talking about.
	165	*/
	166	static void kvm_notify(struct virtqueue *vq)
	167	{
	168	struct kvm_vqconfig *config = vq->priv;
	169
	170	kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, config->address);
	171	}
	172
173	/*
174	* This routine finds the first virtqueue described in the configuration of
175	* this device and sets it up.
176	*/
177	static struct virtqueue kvm_find_vq(struct virtio_device vdev,
9499f5e7 RR	178	unsigned index,
	179	void (callback)(struct virtqueue vq),
	180	const char *name)
e976a2b9 CB	181	{
	182	struct kvm_device *kdev = to_kvmdev(vdev);
	183	struct kvm_vqconfig *config;
	184	struct virtqueue *vq;
	185	int err;
	186
	187	if (index >= kdev->desc->num_vq)
	188	return ERR_PTR(-ENOENT);
	189
	190	config = kvm_vq_config(kdev->desc)+index;
	191
17f34580	192	err = vmem_add_mapping(config->address,
db405988 RR	193	vring_size(config->num,
db405988 RR	194	KVM_S390_VIRTIO_RING_ALIGN));
17f34580	195	if (err)
e976a2b9	196	goto out;
e976a2b9	197
87c7d57c RR	198	vq = vring_new_virtqueue(config->num, KVM_S390_VIRTIO_RING_ALIGN,
87c7d57c RR	199	vdev, (void *) config->address,
9499f5e7	200	kvm_notify, callback, name);
e976a2b9 CB	201	if (!vq) {
	202	err = -ENOMEM;
	203	goto unmap;
	204	}
	205
	206	/*
	207	* register a callback token
	208	* The host will sent this via the external interrupt parameter
	209	*/
	210	config->token = (u64) vq;
	211
	212	vq->priv = config;
	213	return vq;
	214	unmap:
17f34580	215	vmem_remove_mapping(config->address,
db405988 RR	216	vring_size(config->num,
db405988 RR	217	KVM_S390_VIRTIO_RING_ALIGN));
e976a2b9 CB	218	out:
	219	return ERR_PTR(err);
	220	}
	221
	222	static void kvm_del_vq(struct virtqueue *vq)
	223	{
	224	struct kvm_vqconfig *config = vq->priv;
	225
	226	vring_del_virtqueue(vq);
17f34580	227	vmem_remove_mapping(config->address,
db405988 RR	228	vring_size(config->num,
db405988 RR	229	KVM_S390_VIRTIO_RING_ALIGN));
e976a2b9 CB	230	}
e976a2b9 CB	231
d2a7ddda MT	232	static void kvm_del_vqs(struct virtio_device *vdev)
	233	{
	234	struct virtqueue vq, n;
	235
	236	list_for_each_entry_safe(vq, n, &vdev->vqs, list)
	237	kvm_del_vq(vq);
	238	}
	239
	240	static int kvm_find_vqs(struct virtio_device *vdev, unsigned nvqs,
	241	struct virtqueue *vqs[],
	242	vq_callback_t *callbacks[],
	243	const char *names[])
	244	{
	245	struct kvm_device *kdev = to_kvmdev(vdev);
	246	int i;
	247
	248	/* We must have this many virtqueues. */
	249	if (nvqs > kdev->desc->num_vq)
	250	return -ENOENT;
	251
	252	for (i = 0; i < nvqs; ++i) {
	253	vqs[i] = kvm_find_vq(vdev, i, callbacks[i], names[i]);
	254	if (IS_ERR(vqs[i]))
	255	goto error;
	256	}
	257	return 0;
	258
	259	error:
	260	kvm_del_vqs(vdev);
	261	return PTR_ERR(vqs[i]);
	262	}
	263
e976a2b9 CB	264	/*
	265	* The config ops structure as defined by virtio config
	266	*/
	267	static struct virtio_config_ops kvm_vq_configspace_ops = {
5ca9fd54	268	.get_features = kvm_get_features,
c624896e	269	.finalize_features = kvm_finalize_features,
e976a2b9 CB	270	.get = kvm_get,
	271	.set = kvm_set,
	272	.get_status = kvm_get_status,
	273	.set_status = kvm_set_status,
	274	.reset = kvm_reset,
d2a7ddda MT	275	.find_vqs = kvm_find_vqs,
d2a7ddda MT	276	.del_vqs = kvm_del_vqs,
e976a2b9 CB	277	};
	278
	279	/*
	280	* The root device for the kvm virtio devices.
	281	* This makes them appear as /sys/devices/kvm_s390/0,1,2 not /sys/devices/0,1,2.
	282	*/
37f1c012	283	static struct device *kvm_root;
e976a2b9 CB	284
	285	/*
	286	* adds a new device and register it with virtio
	287	* appropriate drivers are loaded by the device model
	288	*/
b769f579	289	static void add_kvm_device(struct kvm_device_desc *d, unsigned int offset)
e976a2b9 CB	290	{
	291	struct kvm_device *kdev;
	292
	293	kdev = kzalloc(sizeof(*kdev), GFP_KERNEL);
	294	if (!kdev) {
b769f579 RR	295	printk(KERN_EMERG "Cannot allocate kvm dev %u type %u\n",
b769f579 RR	296	offset, d->type);
e976a2b9 CB	297	return;
	298	}
	299
37f1c012	300	kdev->vdev.dev.parent = kvm_root;
e976a2b9 CB	301	kdev->vdev.id.device = d->type;
	302	kdev->vdev.config = &kvm_vq_configspace_ops;
	303	kdev->desc = d;
	304
	305	if (register_virtio_device(&kdev->vdev) != 0) {
b769f579 RR	306	printk(KERN_ERR "Failed to register kvm device %u type %u\n",
b769f579 RR	307	offset, d->type);
e976a2b9 CB	308	kfree(kdev);
	309	}
	310	}
	311
	312	/*
	313	* scan_devices() simply iterates through the device page.
	314	* The type 0 is reserved to mean "end of devices".
	315	*/
	316	static void scan_devices(void)
	317	{
	318	unsigned int i;
	319	struct kvm_device_desc *d;
	320
	321	for (i = 0; i < PAGE_SIZE; i += desc_size(d)) {
	322	d = kvm_devices + i;
	323
	324	if (d->type == 0)
	325	break;
	326
b769f579	327	add_kvm_device(d, i);
e976a2b9 CB	328	}
	329	}
	330
cefa33e2 AG	331	/*
	332	* match for a kvm device with a specific desc pointer
	333	*/
	334	static int match_desc(struct device dev, void data)
	335	{
	336	if ((ulong)to_kvmdev(dev_to_virtio(dev))->desc == (ulong)data)
	337	return 1;
	338
	339	return 0;
	340	}
	341
	342	/*
	343	* hotplug_device tries to find changes in the device page.
	344	*/
	345	static void hotplug_devices(struct work_struct *dummy)
	346	{
	347	unsigned int i;
	348	struct kvm_device_desc *d;
	349	struct device *dev;
	350
	351	for (i = 0; i < PAGE_SIZE; i += desc_size(d)) {
	352	d = kvm_devices + i;
	353
	354	/* end of list */
	355	if (d->type == 0)
	356	break;
	357
	358	/* device already exists */
	359	dev = device_find_child(kvm_root, d, match_desc);
	360	if (dev) {
	361	/* XXX check for hotplug remove */
	362	put_device(dev);
	363	continue;
	364	}
	365
	366	/* new device */
	367	printk(KERN_INFO "Adding new virtio device %p\n", d);
	368	add_kvm_device(d, i);
	369	}
	370	}
	371
e976a2b9 CB	372	/*
	373	* we emulate the request_irq behaviour on top of s390 extints
	374	*/
f6649a7e MS	375	static void kvm_extint_handler(unsigned int ext_int_code,
f6649a7e MS	376	unsigned int param32, unsigned long param64)
e976a2b9	377	{
be3c5832 CB	378	struct virtqueue *vq;
be3c5832 CB	379	u16 subcode;
fc678d67	380	u32 param;
e976a2b9	381
f6649a7e	382	subcode = ext_int_code >> 16;
e976a2b9 CB	383	if ((subcode & 0xff00) != VIRTIO_SUBCODE_64)
	384	return;
	385
be3c5832	386	/* The LSB might be overloaded, we have to mask it */
f6649a7e	387	vq = (struct virtqueue *)(param64 & ~1UL);
be3c5832	388
fc678d67	389	/* We use ext_params to decide what this interrupt means */
f6649a7e	390	param = param32 & VIRTIO_PARAM_MASK;
be3c5832	391
fc678d67 AG	392	switch (param) {
	393	case VIRTIO_PARAM_CONFIG_CHANGED:
	394	{
be3c5832 CB	395	struct virtio_driver *drv;
	396	drv = container_of(vq->vdev->dev.driver,
	397	struct virtio_driver, driver);
	398	if (drv->config_changed)
	399	drv->config_changed(vq->vdev);
fc678d67 AG	400
	401	break;
	402	}
cefa33e2 AG	403	case VIRTIO_PARAM_DEV_ADD:
	404	schedule_work(&hotplug_work);
	405	break;
fc678d67 AG	406	case VIRTIO_PARAM_VRING_INTERRUPT:
fc678d67 AG	407	default:
be3c5832	408	vring_interrupt(0, vq);
fc678d67 AG	409	break;
fc678d67 AG	410	}
e976a2b9 CB	411	}
	412
	413	/*
	414	* Init function for virtio
	415	* devices are in a single page above top of "normal" mem
	416	*/
	417	static int __init kvm_devices_init(void)
	418	{
	419	int rc;
	420
	421	if (!MACHINE_IS_KVM)
	422	return -ENODEV;
	423
035da16f	424	kvm_root = root_device_register("kvm_s390");
37f1c012 CH	425	if (IS_ERR(kvm_root)) {
37f1c012 CH	426	rc = PTR_ERR(kvm_root);
e976a2b9 CB	427	printk(KERN_ERR "Could not register kvm_s390 root device");
	428	return rc;
	429	}
	430
cc835f78	431	rc = vmem_add_mapping(real_memory_size, PAGE_SIZE);
17f34580	432	if (rc) {
035da16f	433	root_device_unregister(kvm_root);
17f34580	434	return rc;
e976a2b9 CB	435	}
e976a2b9 CB	436
cc835f78	437	kvm_devices = (void *) real_memory_size;
e976a2b9	438
cefa33e2 AG	439	INIT_WORK(&hotplug_work, hotplug_devices);
cefa33e2 AG	440
e976a2b9 CB	441	ctl_set_bit(0, 9);
	442	register_external_interrupt(0x2603, kvm_extint_handler);
	443
	444	scan_devices();
	445	return 0;
	446	}
	447
faeba830 CB	448	/* code for early console output with virtio_console */
	449	static __init int early_put_chars(u32 vtermno, const char *buf, int count)
	450	{
	451	char scratch[17];
	452	unsigned int len = count;
	453
	454	if (len > sizeof(scratch) - 1)
	455	len = sizeof(scratch) - 1;
	456	scratch[len] = '\0';
	457	memcpy(scratch, buf, len);
	458	kvm_hypercall1(KVM_S390_VIRTIO_NOTIFY, __pa(scratch));
	459	return len;
	460	}
	461
c4de0c1a	462	static int __init s390_virtio_console_init(void)
faeba830	463	{
c4de0c1a HB	464	if (!MACHINE_IS_KVM)
	465	return -ENODEV;
	466	return virtio_cons_early_init(early_put_chars);
faeba830	467	}
c4de0c1a HB	468	console_initcall(s390_virtio_console_init);
c4de0c1a HB	469
faeba830	470
e976a2b9 CB	471	/*
	472	* We do this after core stuff, but before the drivers.
	473	*/
	474	postcore_initcall(kvm_devices_init);